On Wednesday, former tennis star James Blake was mistakenly detained by police, and he says the officer who mistook him for a suspect used "blatant" excessive force!

The 35-year-old appeared on Good Morning America to open up about the traumatic incident in which he was "body-slammed" and handcuffed by a plainclothes NYPD officer while he was standing outside his hotel!

Blake said he was detained for about 15 minutes by at least four plainclothes officers. The half African American athlete tried to explain to the cops that they had the wrong guy, but none of the officers listened to him!